There are two main categories of hypersomnia: primary hypersomnia (sometimes called idiopathic hypersomnia) and recurrent hypersomnia (sometimes called idiopathic recurrent hypersomnia). Both are characterized by similar signs and symptoms and differ only in the frequency and regularity with which the symptoms occur.
Primary hypersomnia is characterized by excessive daytime sleepiness over a long period of time. The symptoms are present all, or nearly all, of the time. Recurring hypersomnia involves periods of excessive daytime sleepiness that can last from one to many days, and recur over the course of a year or more. The primary difference between this and primary hypersomnia is that persons experiencing recurring hypersomnia will have prolonged periods where they do not exhibit any signs of hypersomnia, whereas persons experiencing primary hypersomnia are affected by it nearly all the time. Idiopathic hypersomnia is much like narcolepsy, except there is no cataplexy, no sleep paralysis, and no rapid eye movement when the victim first falls asleep.
Various treatments including prescription drugs have been used to treat hypersomnia without significant success, and no substantial body of evidence supports the effectiveness of any of these treatments. Stimulants are not generally recommended to treat hypersomnia as they treat the symptoms but not the base problem. There is a need for more effective treatments of hypersomnia, especially using administration routes that allow for better drug delivery and patient compliance.